Error Writing "Null" to Tag

Hi, i am getting an error when i create a display and link it to PLC tag.
Please find below error message.
"The node id refers to a node that does not exist in the server address space. "
Even though it is available in both PLC and also in ignition

Any help is appreciated.

Thanks,
Bhanu

Details, please. What OPC Server type (if external) or driver type (if Ignition internal) ? What kind of PLC? What is your actual OPC Item? What is it in the PLC?